In our previous studies, a decreased blood pressure was reported in children treated by anthracycline (AC). The aim of this study was to assess the long-term effects of AC anticancer therapy in 45 subjects aged 13-22 years by repeated 24-hour Holter monitoring of blood pressure. Sixty four aged-matched subjects served as controls. The differences between mean values of systolic (SBP) and diastolic blood pressure (DBP) in each hour of both groups were evaluated by Mann-Whitney test. Also the parameters of the least-squares fit of the sinusoidal curve in each subject were estimated (M - mesor, midline-estimating, a mean value of sinusoidal curve corresponds to 24-hours mean pressure; A - amplitude, double amplitude corresponds to nightday difference; Acr - acrophase is a time of maximal value of a sinusoidal curve). SBP and DBP was significantly lower only during night hours in anthracycline patients 19-22 years old. Also M was lower in this age subgroup of patients comparing to age matched controls (SBP: 112±6 mm Hg versus 117±7 mm Hg, p<0.05; DBP: 67±3 mm Hg versus 69±6 mm Hg, p<0.05), A was not different, Acr in patients was shifted one hour earlier (SBP: 2.4 p.m. versus 3.6 p.m., p<0.05; DBP: 2.1 p.m. versus 3.3 p.m., p<0.01). This corresponds to the shift of the morning blood-pressure increase seen on 24-hours blood pressure profiles. M correlated with age in controls (SBP: r=0.374, p<0.01; regression coefficient b=1.34 mm Hg/1 year; DBP: r=0.365, p<0.01; b=0.95 mm Hg/1 year), but not in patients (SBP: r=0.182, DBP: r=0.064). A and Acr were age-independent in all subjects. It is concluded that blood pressure in 19-22 years old AC patients is lower during night hours, the age-dependent increase of blood pressure seen in healthy controls between 13 and 22 years of age does not occur in patients. This finding is consistent with the long-lasting impairment of the sympathetic nervous system caused by anthracyclines., Z. Nováková ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
a1_Non-invasive methods of determination of baroreflex sensitivity (BRS, ms/mmHg) are based on beat-to-beat systolic blood pressure and inter-beat interval recording. Sequential methods and spectral methods at spontaneous breathing include transient superposition of breathing and 0.1 Hz rhythms. Previously, a cross-spectral method of analysis was used, at constant breathing rate using a metronome set at 0.33 Hz, enabling separate determination of BRS at 0.1 Hz (BRS0.1Hz) and respiratory rhythms (BRS0.33Hz). The aim of the present study was to evaluate the role of breathing in the spectral method of BRS determination with respect to age and hypertension. Such information would be important in evaluation of BRS at pathological conditions associated with extremely low BRS levels. Blood pressure was recorded by Finapres (5 minutes, controlled breathing at 0.33 Hz) in 118 healthy young subjects (YS: mean age 21.0±1.3 years), 26 hypertensive patients (HT: mean age 48.6±10.3 years) with 26 age-matched controls (CHT: mean age 46.3±8.6 years). A comparison of BRS0.1Hz and BRS0.33Hz was made. Statistically significant correlations were found between BRS0.1Hz and BRS0.33Hz in all groups: YS: r=0.52, p<0.01, HT: r=0.47, p<0.05, and CHT: r=0.70, p<0.01. The regression equations indicated the existence of a breathing-dependent component unrelated to BRS (YS: BRS0.33Hz=2.63+1.14*BRS0.1Hz; HT: BRS0.33Hz=3.19+0.91*BRS0.1Hz; and CHT: BRS0.33Hz=1.88+ +1.01*BRS0.1Hz; differences between the slopes and the slope of identity line were insignificant). The ratios of BRS0.1Hz to BRS0.33Hz were significantly lower than 1 (p<0.01) in all groups (YS: 0.876±0.419, HT: 0.628±0.278, and CHT: 0.782±0.260). Thus, BRS evaluated at the breathing rate overestimates the real baroreflex sensitivity. This is more pronounced at low values of BRS, which is more important in patients with pathologic low BRS., a2_For diagnostic purposes we recommend the evaluation of BRS at the frequency of 0.1 Hz using metronome-controlled breathing at a frequency that is substantially higher than 0.1 Hz and is not a multiple of 0.1 Hz to eliminate respiratory baroreflexnon- related influence and resonance effect on heart rate fluctuations., P. Bothová ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy